1. FIELD OF THE INVENTION
The present invention relates to beneficiation processes for ores or minerals, and more particularly to processes for the recovery of pure magnesite from magnesite ores containing magnesite, serpentine and other gangue materials.
2. DESCRIPTION OF THE PRIOR ART
According to our prior patent, U.S. Pat. No. 3,929,627 of Dec. 30, 1975, it is known that a mineral can be separated from its gangue, or the gangue from the mineral contained therein, by rendering in a selective manner the gangue constituents temporarily magnetic and then separating these constituents from the ore by magnetic separators. As taught in this patent, an enhancement in the magnetic behaviour of the gangue constituents to be separated can be achieved by first causing a selective activation of the surface of one or more of the gangue constituents of the ore or mineral and then coating the activated gangue constituents with a finely divided, highly magnetic substance such as magnetite or ferrosilicon, and then two concentrates can be obtained by passing the treated ore or mineral through a magnetic field (e.g. through a wet magnetic separator), i.e., so as to obtain one concentrate composed of the strongly magnetic gangue material, and one concentrate composed of the remainder material. Recovery of the finely ground magnetic material from the surface of the ore or minerals can be achieved by treatment with water under pressure, with detergents, or with agitation in another magnetic field.
The noted first step of selective activation can be achieved by initially conditioning the ore or mineral (in a crushed state) in an aqueous mixture of suitable reagents for activating the surface of the constituents to be magnetically separated, and then conditioning the crushed ore or mineral in an aqueous suspension of a finely divided, strongly magnetic material such as magnetite or ferrosilicon. The initial conditioning of the ore or mineral in order to activate the surface of the constituents to be magnetically separated is achieved, as previously noted, in an aqueous mixture of suitable reagents. According to our previous patent, a suitable aqueous mixture consisted of an aqueous suspension of, by weight, 1 percent diesel oil and 0.15 percent of a mixture of a dialkyl quaternary ammonium chloride such as ARQUAD 2C-75 and primary amines such as ARMAC T and ARMAC C.
However, it has been found that the initial aqueous conditioning mixture of our prior patent has not been found to be entirely satisfactory for a number of reasons, among them being the insufficient stability of the aqueous mixture, the high expense of producing the aqueous mixture, and the insufficient rate of activation of the surface of the constituents to be magnetically separated.
Thus, it is an object of the present invention to provide an aqueous conditioning mixture containing suitable reagents for activating the surface of the intended constituents of the magnesite ores to be magnetically separated from the remaining constituents, which mixture is considerably more stable than the aqueous conditioning mixture disclosed in U.S. Pat. No. 3,929,627.
It is furthermore an object of the present invention to provide an aqueous conditioning mixture of the foregoing type which, as compared to the mixture disclosed in our prior patent, is less expensive to produce and which can achieve the desired results using less amounts of the activating reagents therein.
It is furthermore an object of the present invention to provide an aqueous conditioning mixture of the foregoing type which, as compared to the mixture disclosed in our prior patent, includes components which adsorb or chemisorb (or both) on the particles to be separated at an appreciably faster rate (thus minimizing the required time for conditioning in the mixture); and due to the selective and fast sorption of the components onto the particles to be separated, produces particles having an increased capacity for attracting and accommodating magnetite or ferrosilicon materials. Thus, the ultimate separation efficiency of the beneficiation procedure is greatly enhanced.